DE2822974A1 - METHOD AND DEVICE FOR FILLING AND COVERING A TRITCH - Google Patents

Description

PATENT ADVOCATE

R, SPLANEMANN dr. B. REITZNER J. RICHTER F. WERDERMANN

DIPL.-ING. DIPL.-CHEM. DIPL.-ING. DIPL.-ING.

MONKS

HAMBURG

A / S Akers Mek. Verksted

Oslo Norway

8000 MUNICH 2 £ 6. May 1978

Valley 13

Telephone (089) 226207/226209 Telegrams: Inventius Munich

Our shares:
Your sign:

1113-1-10.349

Patent application

Method and device for refilling and covering a trench

The present invention relates to a method and a Device for use when refilling and covering a trench for a mineral oil or gas pipeline on Sea floor using one at the surface of the water

809849/0880

floating vehicle, which is always held in the correct position above the trench by means of a tracking device, while filling compound is lowered from the vehicle over the ditch or the sea floor.

It is already known to fill such trenches with a barge, which drain sand or other covering material from the water surface through floor hatches over the trench after the vehicle was brought into the correct position over the ditch using tracking devices.

When covering or filling trenches at greater sea depths, such as 100 to 200 m or more, sand, which is emptied from a barge on the surface and sinks through the water to the sea floor, is also distributed over significant areas on both sides of the trench, like this that disproportionate amounts of two covering compound filling the trench required werderuDsrartige are generally lighter with sand from the seabed in areas where the depth is about 30 m which is a normal maximum depth for pumping sand at the sea surface - filled. Such areas are, for example, in central parts of the North Sea about 6 to 8 hours drive from the trench. The previously known uncontrolled covering methods are therefore very costly and time-consuming.

In addition, a lot of time is wasted before emptying a load, until the barge is brought into the correct position over the ditch or the filling point, and you have to, Expect relatively large deviations in position, especially in bad weather.

It is therefore evident that the methods used up to now are very time-consuming and costly, and also a lot Need filling compound.

The purpose of the present invention is therefore to create a method and an apparatus for carrying out the method of the type mentioned at the beginning, whereby the mentioned f & ch parts are eliminated will.

609849/08 * 0

According to the invention, this is indicated in the characterizing part of the following main claim achieved features specified. Further advantageous features of the invention are evident from FIGS Subclaims.

With one embodiment of the present invention is a A filling device created which feeds the trench filling compound at a small distance above the seabed. Like that ensures that the added mass is used entirely to fill the trench. The feed takes place via a relatively roughly measured pipe, which the filling compound with a consistency that is easily pourable and without substantial amounts of water, drains down from the sea surface. The upper part of the pipe consists of a cyclone for separating water from the filling compound, which is carried over a floating hose and in a state that is strongly mixed with water is pumped from a lighter floating at a suitable distance from the cyclone. The cyclone focused the filling compound, which would have to be heavily diluted with water due to the long transport in the hose from the lighter to the vehicle. Such a slurried mass would be filled with great speed directly into the downpipe and during their fall to the seabed and undesirably far from the outlet opening of the pipe are spread. The cyclone is therefore necessary to reduce the rate of fall of the mass, by separating out the most essential proportion of water before the mass is fed into the downpipe.

The mass thus slowly flows down through the pipe and spreads only marginally from the pipe outlet. A suitable number of lighter can be used to fill the mass to lead to the cover area and to be connected to the hose and switched off again in the usual way on the high seas.

The above-mentioned pipe with cyclone is advantageous on a vehicle provided with advantage on an H-3 semi-submersible Platform which has the required satisfactory properties with regard to diving swing and rollers. Under the main deck

009849/0880

-r '

the platform is a smaller platform where the Cyclone is provided. The cyclone is connected to a floating transport hose, and the outlet "for the The separated filling compound is connected to the pipe running to the seabed.

The H-3 platform or the vehicle exhibits advanced Locating devices so that the vehicle with its own screws and machines is always in the desired position above the The trench or the area to be covered. The vehicle can thus be relocated without the use of anchors on the ocean floor. The localization is also carried out in a generally known manner via signal transmitters along the line to be followed Line are provided.

The lower portion of the pipe or the outlet area is over a suitable number of cables or cables connected to, for example, a winch in each corner of the vehicle, whereby some of the winches can be controlled via a computer system. The winches tighten or loosen the respective cables in such a way that the pipe outlet can be relocated so that it is exactly in the desired position. These The position is provided on the vehicle via an am.pipe outlet Transponder monitored and controlled.

The above-mentioned control of the pipe is used to eliminate the displacement of the vehicle, especially in heavy seas applied.

The lower pipe section is designed telescopically, so that the distance between the outlet end and the sea bed or the filling area can always be adapted to the prevailing conditions.

The invention is explained in more detail below with reference to an embodiment shown in the drawing.

Fig. 1 shows a construction according to the invention, which is based on a

809849/0880

semi-submersible vehicle is suspended and seen in view towards the bow area.

Fig. 2 shows the construction in side view.

Fig. 1 shows a rough outline of a semi-submersible platform 1, preferably type H-3, in a submerged working position. The drilling and lifting tower of the platform is marked 2, the main deck with 3 and the water level with 4. The platform columns are with 5, the pontoons with 6, the drive motor with 7 and the side screws or transverse reflector designated by 8.

A support frame 9 is suspended from the steel structures of the platform by means of ropes or stays 10 under the main deck / while Stage II protects the support frame against lateral displacement stiffen. The support frame 9 forms the base for a cyclone separator 12, which is provided on the support frame so that it can be dismantled is. The cyclone is preferably of the type that separates heavy particles from a liquid stream, whereby the particles as a whole along the conical 3hnentmkreis des Cyclones flow downwards and leave the cyclone in the bottom area 13, while the liquid from the upper cyclone area exits via the outlet pipe 14 and the valve 15, the latter two for the purpose of throttling the outflowing Amount of water to determine and change the water content of the filling compound are provided. The heavily mixed with water Filling compound is fed to the cyclone from the floating transport hose 16 via the inlet connection 17. The transport hose 16 is connected to the pump system (not shown) of a barge 18 at the opposite end.

A pipe 19 also runs from the outlet connection 13 of the cyclone 12 large dimensions down to the trench 20 to be covered, which was previously dug to protect the pipeline 22 in the sea bed 21 became. The tube 19 is by means of collars 23 or the like. Divided into sections 24 so that it during the advancing Covering the trench can be adapted to the respective working depth.

809849/0880

The lower tube section is advantageous for carrying out relatively small depth adjustments of the lower end section of the tube 19 telescopic and can thus be adjusted vertically by means of ropes or cables 26. The cables 26 are connected to the outlet section 28 of the pipe 19 at 27 and run upwards and outwards to the pontoons 6 and further, via rollers or the like 29 to provided on the main deck 3 Winches 30. The winches 30 can of course be an underwater type and directly on the pontoons or on one be provided in another suitable location. The cables 26 also have an important task, namely the control of the pipe outlet 28, so that it is always in the desired position above the trench 20.

Mi lower portion of the tube 19 or of the same in the vicinity is provided a signal receiver 31, which surrounding region is directed against the gap in the pipe socket 28 and the operators on board the mother vehicle always in control, possibly via a computerized system via the covering process enables. A number of signal jacks 32 are provided along the trench line so that the relationship between the vehicle and the trench can always be corrected.

009849/0880

Blank page

Claims (4)

Claims lj method for refilling or covering a trench for a mineral oil and / or gas pipeline on the seabed when using a surface vehicle / which means Locating devices is held in a suitable position above the trench, while filling compound to the trench or seabed is unloaded from the vehicle, characterized in that the filling compound in strong with water mixed state the surface vehicle from a supply or the like. By a preferably floating hose is supplied that the water content of the filling compound is reduced in a separator on board the vehicle mentioned and that the filling compound treated in this way is passed in a manner known per se through a pipe or the like, the mouth of which is in the vicinity of the trench or sea bed is held, is led to the trench or sea bed. 2. Device for performing the method according to claim 1, characterized in that that they have a cyclone separator (12) attached to the vehicle (1) with an inlet (17) for filling material mixed with water, an upper outlet (14) for water and a lower outlet (13) for the filling compound with reduced water content; a pipe or the like. (19) which is connected at one end to the lower outlet (13) of the separator (12) and to the other end (27) of which has a plurality of ropes or the like. (26) is attached, the ropes or the like. (26) in different Directions run upwards to any rollers (29) and winches (30) on the vehicle (1); and means (31) for Determination of the position of the lower end of the pipe in relation to the pipeline (22) or signal transmitter provided along the same (32) includes. 3. Apparatus according to claim 2, characterized in that it has means for completely or partially automatic control of the winches (30) for local adjustment of the outlet (28) of the pipe or the like (19) having. 809849/0800 4. Apparatus according to claim 2 or 3, characterized characterized in that the upper outlet (14) of the separator (12) has a control device (15) for the Has flow rate. 809849/0880